a(n) = A007090(A000040(n)). - Jonathan Vos Post (jvospost2(AT)yahoo.com), Sep 09 2006
CROSSREFS
Cf. A004676 = Primes written in base 2, A001363 = Primes in ternary, A004679 = Primes written in base 5. A004680 = Primes written in base 6, A004681 = Primes written in base 7. A004682 = Primes written in base 8, A004683 = Primes written in base 9, A004684 = Primes written in base 11, A072805 = Primes of form 4k+3 written in base 3.